Sithin Mathew, Weed Science Graduate Student, Eric Yu, UMN Extension Crops Educator, and Debalin Sarangi, Extension Weed Scientist Herbicides often require the use of adjuvants to maximize weed control efficacy and minimize application-related risks. Although some herbicide formulations contain built-in adjuvant packages, few are designed to optimize performance across the wide range of environmental and application conditions. Therefore, the applicator often needs additional adjuvants to optimize the herbicide application for the specific conditions of the area being treated. The most commonly used adjuvants can be grouped into four categories: 1) activator adjuvants [e.g., nonionic surfactant (NIS), crop oil concentrate (COC), and methylated seed oil (MSO), etc.], 2) water conditioners [e.g., ammonium sulfate (AMS), and volatility reduction agent (VRA), etc.], 3) spray solution modifiers [e.g., antifoam agents, and drift reduction agents (DRA)], and 4) adjuvant mixtures. Adjuvan...
